For many sports it is important for a player to develop hand-eye coordination. This is especially true in baseball where a batter must hit a fast-moving ball with a bat. Developing the necessary coordination to hit a baseball can take considerable time. Over the years, various methods have been developed to teach this skill. One method includes placing a ball on a stationary pole or tee, whereupon the batter attempts to hit the ball off the tee. Using a tee develops basic hand-eye coordination, but does not allow a batter to practice hitting a moving ball.
Another method uses a ball permanently fastened to the first end of a rope. A "pitcher" holds the second end of the rope and swings the ball around in a circle. The batter stands outside the orbit of the moving ball and attempts to hit the ball with the bat. The second end of the rope can be attached to a pole. The pole helps the ball achieve greater centrifugal motion and gives the pitcher more control of the movement of the ball.
Previous practice devices of this type were effective in helping a batter develop hand-eye coordination, but these devices had shortcomings. If the pole was small enough to be held by the pitcher, the pitcher was required to hold the entire device and use his body to counteract the swinging motion of the ball. Ordinarily this would quickly fatigue the pitcher. On the other hand, if the pole was too long to be held by the pitcher, the pole was permanently mounted in the ground. This solution compromised the portability of the device and limited the pitcher's control of the movement of the ball.
Most previous practice devices required a hole to be drilled into the ball for attachment to the rope. This prevented use of the ball in other applications, and also did not allow inexpensive replacement of the ball with standard baseballs. Replacement is important because the ball will become damaged or worn after repeated use. Furthermore, it is more economical and inexpensive to allow replacement of the ball with common baseballs or softballs that do not require any special mounting operations.
The devices that did not require drilling a hole in the ball were adapted to allow the use of only one size of ball. If the batter desired to practice hitting a ball of a different size, a different apparatus would have to be used.